One of the basic rules of tennis applies here: If you want to improve your skills, you need to play someone who is (at a minimum) at your own level. As sophisticated as a 20-something may be, she will be more so—with a more exquisite bullshit detector—in her 40s. When older men date much younger women, they cheat themselves out of an opportunity to be matched with a partner with the maturity to see them as they really are. Depression, the research shows, peaks for men in their mid-to-late 40s. In the face of statistics like those, middle-aged men can’t afford to choose partners who lack the life experience to provide the right kind of challenge.